AMG Systems Ltd. reserves the right to make changes to this
document without notice. The information herein is believed to
be accurate. No responsibility is assumed by AMG for its use.
Page 6 of 12
AMG3782ERN Instruction Sheet
D18979-00.doc
Ethernet Operation
In order for the AMG system to transmit Ethernet signals, an onboard RJ45 Ethernet interface or
X16003 Ethernet interface adaptor should be fitted to all units in the ring.
The Ethernet interface can operate at either 10Mbits/s half duplex, or 100Mbit/s full duplex. When all
the Ethernet interfaces around the ring are operating at 100Mbit/s full duplex the system behaves as a
multi-port repeater. Data transmitted on any one port is transmitted out on all other ports with the
minimum of delay or buffering. The nominal bandwidth available for Ethernet transmission within the
ring is 100Mbit/s when Ethernet only, or 50MBit/s when the low speed data option is also used. If one
node is transmitting, the entire bandwidth is available for this traffic. If multiple nodes transmit
simultaneously on the ring, then the bandwidth is shared between each node as required. With similar
traffic at each node the sharing would be nominally equal.
Although the limit for the number of video channels which can be transmitted around the ring is eight,
up to 64 nodes can be attached for distributing Ethernet signals with the bandwidth sharing
implemented. The units use Flow Control (Pause Frames) to limit the access to the ring to share the
bandwidth and to ensure that no data is lost. When an Ethernet port is operating at 10Mbits/s half
duplex, this port will now only receive data from a receive unit rather than all ports as when operating
at 100Mbits/s full duplex.
The 100BaseT port does not implement MDI/MDIX; it should be connected with a straight though
cable to an external switch port and with a cross over cable when connected directly to a PC or DTE.
